/Engine/Plugins/FX/Niagara/Source/NiagaraEditor/Public/NiagaraActions.h
If a node displays its options 'inline' (title right widget), you can configure the way the combo button content is displayed and give it a tooltip.
struct FInlineMenuDisplayOptions
bool
bDisplayInline
This needs to be true to have any effect, as it will determine widget generation in the title right area of the node.
constFSlateBru...
DisplayBrush
FText
DisplayName
FText
TooltipText